[light emitting diode array illuminant and backlight module by using the same]

ABSTRACT

The present invention provides a light emitting diode array illuminant and a backlight module by using the same, which comprises at least a carrier and a plurality of light emitting diodes. The carrier comprises a front surface and a back surface, and a plurality set of contacts are disposed on the front surface and back surface of the carrier. The light emitting diodes are disposed on the carrier, and are electrically connected to the contacts of each set, respectively. The illuminant provided by the light emitting diodes emits a light from a side of the carrier. The present invention further applies the light emitting diode array illuminant to a backlight module, so that it can be activated under low temperature and also protects the backlight module from over heating after it is activated.

BACKGROUND OF INVENTION

[0001] 1. Field of Invention

[0002] The present invention relates to an illuminant and a backlightmodule (B/L) by using the same, and more particularly, to a lightemitting diode (LED) array illuminant and a backlight module by usingthe same.

[0003] 2. Description of Related Art

[0004] The video products, especially the digital video or image devicehas become a common used product in general daily life. Within variousdigital video or image devices, the display is one significant elementfor displaying related information. The user can read information fromthe display, and further controls the operation of the device. Further,the size of the video or image device is getting thinner and lighter dayby day for adapting with the pace of the modern life. Although theconventional Cathode Ray Tube (CRT) display has its advantages, since ittakes a large size and consumes a great amount of electricity.Accordingly, in accordance with the photoelectricity technology and thesemiconductor fabrication technology, the panel display, such as theLiquid Crystal Display (LCD), has developed and become the most populardisplay product now.

[0005] Since the LCD is a non self-emitting type display, in order toachieve the object of displaying, an illuminant, which can provide asufficient light, has to be provided. According to various utilizationtypes of the illuminant, the LCD can be categorized into thetransmissive LCD, the reflective LCD, and the trans-reflective LCD. Forexample, the transmissive LCD or the trans-reflective LCD usually uses abacklight module as its main illuminant, and the backlight module isusually made of the components including a cold cathode fluorescent lamp(CCFL), which is used as an illuminant, a light guide panel (LGP), areflective panel, and a lamp holder as shown in FIG. 1.

[0006]FIG. 1 schematically shows a sectional view of a conventionalbacklight module of the notebook computer. Referring to FIG. 1, theconventional backlight module 100 mainly comprises a CCFL 102, which isused as an illuminant, a light guide panel 104, and a lamp holder 106.Wherein, the light guide panel 104 comprises a light incident surface103 a, a light emitting surface 103 b, and a light dispersing surface103 c. The lamp holder 106 is disposed correspondingly to the lightincident surface 103 a of the light guide panel 104, and the lamp 102 isdisposed in the lamp holder 106, so that the light emitted from the lamp102 is incident to the light guide panel 104 after it is gathered by thelamp 106.

[0007] However, since the diameter of the CCFL 102 is limited, thethickness of the overall backlight module is hard to reduce. Further,after long time operation, since the temperature rises, the portion ofthe light guide panel 104 near to the CCFL is easily to be yellowed, andfurther results in the problems of uneven color and the warped lightguide panel 104. Further, the conventional CCFL 102 is not easy toactivate under low temperature, in order to obtain an expectedbrightness, the CCFL 102 must warp up first in the early phase when thelamp is activated.

SUMMARY OF INVENTION

[0008] It is an object of the present invention to provide a lightemitting diode array illuminant and a backlight module by using thesame, so as to prevent the problems of the light guide panel yellowed ordeformation from happening.

[0009] It is an further object of the present invention to provide alight emitting diode array illuminant and a backlight module by usingthe same, so as to reduce the thickness of the overall backlight module.

[0010] It is an another object of the present invention to provide alight emitting diode array illuminant and a backlight module by usingthe same, which can be activated under low temperature and without theprocess of warming up.

[0011] It is a further another object of the present invention toprovide a light emitting diode array illuminant and a backlight moduleby using the same, so as to increase the brightness.

[0012] In accordance with the object mentioned above and others, thepresent invention provides a light emitting diode array illuminant,which comprises a carrier and a plurality of light emitting diodes.Wherein, the carrier comprises a front surface and a back surface, and aplurality set of contacts are disposed on the front surface and backsurface of the carrier. The light emitting diodes are disposed on thecarrier, wherein each light emitting diode is electrically connected tothe contact of each set, respectively. The illuminant provided by thelight emitting diodes emits a light from a side of the carrier.

[0013] The present invention further provides a light emitting diodearray illuminant, which comprises a folded flexible printed circuit(FPC) plate and a plurality of light emitting diodes. The folded FPCplate comprises a first join area, a second join area, and a bendingarea, which connected to the first join area and the second join area.Wherein, the first join area comprises a plurality set of firstcontacts, and the second join area comprises a plurality set of secondcontacts. Further, the light emitting diodes are disposed on the firstjoin area and the second join area, wherein each light emitting diode iselectrically connected to the first contact of each set and the secondcontact of each set, and the illuminant provided by the light emittingdiodes emits a light from a side of the folded FPC plate.

[0014] The present invention further provides a backlight module, whichcomprises a light guide panel and a light emitting diode arrayilluminant. Wherein, the light guide panel comprises a light incidentsurface, a light emitting surface, and a light dispersing surface. Thelight emitting diode array illuminant is disposed beside the lightincident surface of the light guide panel. The light emitting diodearray illuminant comprises a carrier and a plurality of light emittingdiodes, wherein the carrier comprises a front surface and a backsurface, and a plurality set of contacts are disposed on the frontsurface and back surface of the carrier. The light emitting diodes aredisposed on the carrier, wherein each light emitting diode iselectrically connected to the contact of each set, respectively. Theilluminant provided by the light emitting diodes emits a light from aside of the carrier.

[0015] The present invention further provides a backlight module, whichcomprises a light guide panel and a light emitting diode arrayilluminant, wherein the light guide panel comprises a light incidentsurface, a light emitting surface, and a light dispersing surface. Thelight emitting diode array illuminant is disposed beside the lightincident surface of the light guide panel, and comprises a folded FPCplate and a plurality of light emitting diodes. The folded FPC platecomprises a first join area, a second join area, and a bending area,which connected to the first join area and the second join area.Wherein, the first join area comprises a plurality set of firstcontacts, and the second join area comprises a plurality set of secondcontacts. Further, the light emitting diodes are disposed on the firstjoin area and the second join area, wherein each light emitting diode iselectrically connected to the first contact of each set and the secondcontact of each set, and the illuminant provided by the light emittingdiodes emits a light from a side of the folded FPC plate.

[0016] The present invention uses a carrier and a plurality of lightemitting diodes as an illuminant, so as to increase the brightness andprevent the conventional lamp high temperature problem resulted from thelong time operation of the lamp from happening. Further, the thicknessof the backlight module is not limited by the diameter of the CCFL as inthe prior art. Accordingly, the illuminant according to the presentinvention can be activated under low temperature and the warm up time isalso reduced.

BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention, and together with the description, serve to explain theprinciples of the invention.

[0018]FIG. 1 schematically shows a sectional view of a conventionalbacklight module of the notebook computer.

[0019]FIG. 2 schematically shows a sectional view of a backlight moduleof a first embodiment according to the present invention.

[0020]FIG. 3A schematically shows a sectional view of a backlight moduleof a second embodiment according to the present invention.

[0021]FIG. 3B schematically shows a top view expansion diagram of alight emitting diode array illuminant of the backlight module in FIG.3A.

[0022]FIG. 4A schematically shows a sectional view of a backlight moduleof a third embodiment according to the present invention.

[0023]FIG. 4B schematically shows a top view expansion diagram of alight emitting diode array illuminant of the backlight module in FIG.4A.

DETAILED DESCRIPTION

[0024] The major concept of the present invention is in that theilluminant of the backlight module in the LCD is constituted of acarrier and a plurality of light emitting diodes. The backlight moduleformed by using this concept has at least three types. Further detailsare described with referring to FIG. 2, FIG. 3A, FIG. 3B, FIG. 4A, andFIG. 4B hereinafter.

[0025] The First Embodiment: FIG. 2 schematically shows a sectional viewof a backlight module (B/L) of a first embodiment according to thepresent invention.

[0026] Referring to FIG. 2, the backlight module 200 of the presentembodiment comprises a light emitting diode (LED) array illuminant 202and a light guide panel (LGP) 204, wherein the light guide panel 204comprises a light incident surface 203 a, a light emitting surface 203b, and a light dispersing surface 203 c. The light emitting diode arrayilluminant 202 is disposed beside the light incident surface 203 a ofthe light guide panel 204. The light emitting diode array illuminant 202comprises a carrier 206 and a plurality of light emitting diodes 208,wherein the carrier 206 comprises a front surface 207 a and a backsurface 277 b, and a plurality set of contacts 210 are disposed on thefront surface 207 a and the back surface 207 b of the carrier 206. Thecarrier 206 is such as a Printed Circuit Board (PCB), and the lightemitting diode 208 is such as a surface adhesion type light emittingdiode element.

[0027] Referring to FIG. 2, the light emitting diodes 208 is disposed onthe carrier 206, and each light emitting diode 208 is electricallyconnected to the contact 210 of each set, respectively. The illuminantprovided by the light emitting diodes 208 emits a light from a side ofthe carrier 206. Further, if the light emitting diode 208 is a surfaceadhesion type light emitting diode, each light emitting diode 208comprises a set of electrodes (not shown). The light emitting diodes 208are electrically connected to the contacts 210 via the electrodesrespectively and the light emitting diodes 208 are symmetricallydisposed with each other or interleaved disposed. Further, a reflectivepanel 205 is disposed on the light dispersing surface 203 c of the lightguide panel 204, and some optical plates such as the diffusion platesand the light enhancement plates can be disposed on the light emittingsurface 203 b of the light guide panel 204.

[0028] The Second Embodiment: FIG. 3A schematically shows a sectionalview of a backlight module of a second embodiment according to thepresent invention.

[0029] Referring to FIG. 3A, the backlight module 300 of the presentembodiment comprises a light emitting diode array illuminant 302 and alight guide panel 304, wherein the light guide panel 304 comprises alight incident surface 303 a, a light emitting surface 303 b, and alight dispersing surface 303 c. The light emitting diode arrayilluminant 302 is disposed beside the light incident surface 303 a ofthe light guide panel 304 and comprises a folded flexible printedcircuit (FPC) plate 306 and a plurality of light emitting diodes 308.The folded FPC plate 306 comprises a first join area 307 a, a secondjoin area 307 b, and a bending area 307 c, which connected to the firstjoin area 307 a and the second join area 307 b. Wherein, the first joinarea 307 a comprises a plurality set of first contacts 310 a, and thesecond join area 307 b comprises a plurality set of second contacts 310b. The FPC plate 306 may be a single layer FPC plate or a multi-layerFPC plate, and the light emitting diode 308 is such as a surfaceadhesion type light emitting diode element.

[0030] Referring to FIG. 3A, the light emitting diodes 308 are disposedon the first join area 307 a and the second join area 307 b, whereineach light emitting diode 308 is electrically connected to the firstcontact 310 a of each set and the second contact 310 b of each set, andthe illuminant provided by the light emitting diodes 308 emits a lightfrom a side of the folded FPC plate 306. Further, if the light emittingdiode 308 is a surface adhesion type light emitting diode, each lightemitting diode 308 comprises a set of electrodes (not shown). The lightemitting diodes 308 are electrically connected to the first contact 310a and the second contact 310 b via the electrodes, respectively. Thelight emitting diodes 308 electrically connected to the first contact310 a and the light emitting diodes 308 electrically connected to thesecond contact 310 b are symmetrically disposed with each other orinterleaved disposed. Further, a reflective panel 305 is disposed on thelight dispersing surface 303 c of the light guide panel 304, and someoptical plates such as the diffusion plates and the light enhancementplates can be disposed on the light emitting surface 303 b of the lightguide panel 304.

[0031] The light emitting diode array illuminant 302 of the presentembodiment is described with referring to FIG. 3B hereinafter.

[0032]FIG. 3B schematically shows a top view expansion diagram of alight emitting diode array illuminant of the backlight module in FIG.3A. Referring to FIG. 3B, the FPC plate 306 in the light emitting diodearray illuminant 302 comprises a first join area 307 a, a second joinarea 307 b, and a bending area 307 c, which is connected to the firstjoin area 307 a and the second join area 307 b, and the light emittingdiodes 308 are disposed on the FPC plate 306. The FPC plate 306 shown inthe drawing is then folded from the boding line 320 and inserted intothe backlight module 300 in FIG. 3A.

[0033] The Third Embodiment: FIG. 4A schematically shows a sectionalview of a backlight module of a third embodiment according to thepresent invention.

[0034] Referring to FIG. 4A, the major difference between the backlightmodule 400 of the present embodiment from the backlight module 300 inFIG. 3A as mentioned above is in the style of the light emitting diodearray illuminant 402. The light emitting diode array illuminant 402 ofthe present embodiment comprises a folded FPC plate 406 and a pluralityof light emitting diodes 408. The folded FPC plate 406 comprises a firstjoin area 407 a, a second join area 407 b, and a bending area 407 c,which is connected to the first join area 407 a and the second join area407 b. Wherein, the first join area 407 a comprises a plurality set offirst contacts 410 a, and the second join area 407 b comprises aplurality set of second contact 410 b. The light emitting diode arrayilluminant 402 of the present embodiment is described with referring toFIG. 4B hereinafter.

[0035]FIG. 4B schematically shows a top view expansion diagram of alight emitting diode array illuminant of the backlight module in FIG.4A. Referring to FIG. 4B, the FPC plate 406 in the light emitting diodearray illuminant 402 is folded from the boding line 420 and insertedinto the backlight module 400 in FIG. 4A.

[0036] The present invention is characterized by using a carrier and aplurality of light emitting diodes as an illuminant of the backlightmodule, so as to increase the brightness. Further, the present inventionuses the light emitting diodes as the illuminant, so as to prevent theconventional lamp high temperature problem resulted from the long timeoperation of the lamp from happening. Further, the thickness of thebacklight module of the present invention is not limited by the diameterof the CCFL as in the prior art. Accordingly, the illuminant accordingto the present invention can be activated under low temperature and thewarm up time is also reduced.

[0037] Although the invention has been described with reference to aparticular embodiment thereof, it will be apparent to one of ordinaryskill in the art that modifications to the described embodiment may bemade without departing from the spirit of the invention. Accordingly,the scope of the invention will be defined by the attached claims not bythe above detailed description.

1. A light emitting diode array illuminant, comprising: a carrier,wherein the carrier comprises a front surface and a back surface, and aplurality set of contacts are disposed on the front surface and the backsurface of the carrier; and a plurality of light emitting diodes,disposed on the carrier, wherein the light emitting diodes areelectrically connected to the sets of contacts, respectively, and theilluminant provided by the light emitting diodes emits a light from aside of the carrier.
 2. The light emitting diode array illuminant ofclaim 1, wherein the carrier comprises a Printed Circuit Board (PCB). 3.The light emitting diode array illuminant of claim 1, wherein thecarrier comprises a flexible printed circuit (FPC) plate.
 4. The lightemitting diode array illuminant of claim 3, wherein the FPC plate iseither a single layer FPC plate or a multi-layer FPC plate.
 5. The lightemitting diode array illuminant of claim 1, wherein each of the lightemitting diodes is a surface adhesion type light emitting diode element,and each of the light emitting diodes comprises a set of electrodes, andthe light emitting diodes are electrically connected to the sets ofcontacts via the set of electrodes, respectively.
 6. The light emittingdiode array illuminant of claim 1, wherein the light emitting diodes aresymmetrically disposed with each other or interleaved disposed.
 7. Alight emitting diode array illuminant, comprising: a folded FPC plate,comprising a first join area, a second join area, and a bending area,which is connected to the first join area and the second join area,wherein the first join area comprises a plurality set of first contacts,and the second join area comprises a plurality set of second contacts;and a plurality of light emitting diodes, disposed on the first joinarea and the second join area, wherein the light emitting diodes areelectrically connected to the sets of first contacts and the sets ofsecond contacts, and the illuminant provided by the light emittingdiodes emits a light from a side of the folded FPC plate.
 8. The lightemitting diode array illuminant of claim 7, wherein each of the lightemitting diodes is a surface adhesion type light emitting diode element,and each of the light emitting diodes comprises a set of electrodes, andthe light emitting diodes are electrically connected to the sets offirst contacts and the sets of second contacts via the set ofelectrodes, respectively.
 9. The light emitting diode array illuminantof claim 7, wherein the light emitting diodes electrically connected tothe sets of first contacts and the light emitting diodes electricallyconnected to the sets of second contacts are symmetrically disposed witheach other or interleaved disposed.
 10. A backlight module, comprising:a light guide panel, comprising a light incident surface, a lightemitting surface, and a light dispersing surface; and a light emittingdiode array illuminant, disposed beside the light incident surface ofthe light guide panel, comprising: a carrier, wherein the carriercomprises a front surface and a back surface, and a plurality set ofcontacts are disposed on the front surface and the back surface of thecarrier; and a plurality of light emitting diodes, disposed on thecarrier, wherein the light emitting diodes are electrically connected tothe sets of contacts, respectively, and the illuminant provided by thelight emitting diodes emits a light from a side of the carrier.
 11. Thebacklight module of claim 10, wherein the carrier comprises a PrintedCircuit Board (PCB).
 12. The backlight module of claim 10, wherein thecarrier comprises a flexible printed circuit (FPC) plate.
 13. Thebacklight module of claim 12, further comprising a carrier, wherein theFPC plate is either a single layer FPC plate or a multi-layer FPC plate.14. The backlight module of claim 10, wherein each of the light emittingdiodes is a surface adhesion type light emitting diode element, and eachof the light emitting diodes comprises a set of electrodes, and thelight emitting diodes are electrically connected to the sets of contactsvia the set of electrodes, respectively.
 15. The backlight module ofclaim 10, wherein the light emitting diodes are symmetrically disposedwith each other or interleaved disposed.
 16. The backlight module ofclaim 10, further comprising a reflective panel, wherein the reflectivepanel is disposed on the light dispersing surface.
 17. A backlightmodule, comprising: a light guide panel, comprising a light incidentsurface, a light emitting surface, and a light dispersing surface; and alight emitting diode array illuminant, disposed beside the lightincident surface of the light guide panel, comprising: a folded FPCplate, comprising a first join area, a second join area, and a bendingarea, which is connected to the first join area and the second joinarea, wherein the first join area comprises a plurality set of firstcontacts, and the second join area comprises a plurality set of secondcontacts; and a plurality of light emitting diodes, disposed on thefirst join area and the second join area, wherein the light emittingdiodes are electrically connected to the sets of first contacts and thesets of second contacts, and the illuminant provided by the lightemitting diodes emits a light from a side of the folded FPC plate. 18.The backlight module of claim 17, wherein each of the light emittingdiodes is a surface adhesion type light emitting diode element, and eachof the light emitting diodes comprises a set of electrodes, and thelight emitting diodes are electrically connected to the sets of firstcontacts and the sets of second contacts via the set of electrodes,respectively.
 19. The backlight module of claim 17, wherein the lightemitting diodes electrically connected to the sets of first contacts andthe light emitting diodes electrically connected to the sets of secondcontacts are symmetrically disposed with each other or interleaveddisposed.
 20. The backlight module of claim 17, further comprising areflective panel, wherein the reflective panel is disposed on the lightdispersing surface.